Reactive metal powders in-flight heat treatment processes

Abstract

There are provided reactive metal powder in-flight heat treatment processes. For example, such processes comprise providing a reactive metal powder; and contacting the reactive metal powder with at least one additive gas while carrying out said in-flight heat treatment process, thereby obtaining a raw reactive metal powder.

The invention claimed is: 
     
       1. A reactive metal in-flight heat treatment process comprising:
 contacting a reactive metal with an in-flight heat treatment process gas mixture comprising (i) at least one in-flight heat treatment process gas and (ii) at least one additive gas that is present at a concentration of less than 1000 ppm in said mixture, while carrying out said in-flight heat treatment process to obtain a raw reactive metal powder, wherein the reactive metal source comprises a titanium alloy, and wherein the at least one additive gas comprises an oxygen-containing gas; and 
 diffusing a component of the at least one additive gas into particles of the raw reactive metal powder beneath a surface of the particles to create a concentration profile for the diffused component within the particles; 
 wherein a particle size distribution of about 10 to about 53 μm of said raw reactive metal powder has a flowability less than 40 s, measured according to ASTM B213; and 
 wherein contacting the reactive metal with the in-flight heat treatment process gas mixture while carrying out said in-flight heat treatment process to obtain the raw reactive metal powder comprises maintaining a chemical composition of the reactive metal such that the amount of oxygen within the raw reactive metal powder is below 1800 ppm according to AMS 4998. 
 
     
     
       2. The reactive metal in-flight heat treatment process of  claim 1 , wherein the particles are Ti-6Al-4V particles, and wherein maintaining the chemical composition of the reactive metal comprises maintaining the Ti-6Al-4V particles as Ti-6Al-4V particles. 
     
     
       3. The reactive metal in-flight heat treatment process of  claim 1 , wherein contacting the reactive metal comprises contacting a reactive metal powder. 
     
     
       4. The reactive metal in-flight heat treatment process of  claim 1 , wherein the oxygen-containing gas comprises O2, CO2, CO, NO2, air, water vapor, or a mixture thereof. 
     
     
       5. The reactive metal in-flight heat treatment process of  claim 1 , wherein the at least one additive gas comprises O 2 . 
     
     
       6. The reactive metal in-flight heat treatment process of  claim 1 , wherein the at least one additive gas comprises air. 
     
     
       7. The reactive metal in-flight heat treatment process of  claim 1 , wherein the raw reactive metal powder has a flowability less than 30 s, measured according to ASTM B213. 
     
     
       8. The reactive metal in-flight heat treatment process of  claim 1 , wherein the raw reactive metal powder comprises a powder having a particle size distribution of 25 to 45 μm having a flowability less than 40 s, measured according to ASTM B213. 
     
     
       9. The reactive metal in-flight heat treatment process of  claim 1 , wherein the raw reactive metal powder has a flowability less than 28 s, measured according to ASTM B213. 
     
     
       10. The reactive metal in-flight heat treatment process of  claim 1 , wherein the in-flight heat treatment process gas mixture comprises 80 ppm or less of the at least one additive gas. 
     
     
       11. The reactive metal in-flight heat treatment process of  claim 1 , wherein said process is carried out by means of at least one plasma torch. 
     
     
       12. The reactive metal in-flight heat treatment process of  claim 11 , wherein said at least one plasma torch is a radio frequency (RF) plasma torch. 
     
     
       13. The reactive metal in-flight heat treatment process of  claim 11 , wherein said at least one plasma torch is a direct current (DC) plasma torch. 
     
     
       14. The reactive metal in-flight heat treatment process of  claim 11 , wherein said at least one plasma torch is a microwave (MW) plasma torch. 
     
     
       15. The reactive metal in-flight heat treatment process of  claim 1 , wherein the in-flight heat treatment process gas is provided from at least one plasma source.